Brothers Matthew and Mark Knight and their families have come to the colony planet of Terratertius to escape the the limited life of Earth. Along with nearly seven hundred other like-minded people, the Knights want to return to a more-basic lifestyle and to build a better world for their children. But unknown to the Knights and the other colonists, an alien race long ago claimed Terratertius for themselves, leaving one of their kind behind in hibernation. Now, accidently awakened, the alien asserts its claim. The being will stop at nothing to take control of the planet, including targeting human children.

But no one threatens the Knights!